Fuel cells are electrochemical cells that are being developed for motive and stationary electric power generation. One fuel cell design uses a solid polymer electrolyte (SPE) membrane or proton exchange membrane (PEM), to provide ion transport between the anode and cathode. Gaseous and liquid fuels capable of providing protons are used. Examples include hydrogen and methanol, with hydrogen being favored. Hydrogen is supplied to the fuel cell's anode. Oxygen (as air) is the cell oxidant and is supplied to the cell's cathode. The electrodes are formed of porous conductive materials, such as woven graphite, graphitized sheets, or carbon paper to enable the fuel to disperse over the surface of the membrane facing the fuel supply electrode. Each electrode carries finely divided catalyst particles to promote ionization of hydrogen at the anode and of oxygen at the cathode. Protons flow from the anode through the ionically conductive polymer membrane to the cathode where they combine with oxygen ions to form water, which is discharged from the cell. Conductor plates carry away the electrons formed at the anode. A typical fuel cell is described in U.S. Pat. No. 5,272,017 and U.S. Pat. No. 5,316,871 (Swathirajan et al).
Currently, state of the art PEM fuel cells utilize a membrane made of perfluorinated ionomers such as DuPont's Nafion®. The ionomer carries pendant ionizable groups (e.g. sulfonate groups) for transport of protons through the membrane from the anode to the cathode. But unwanted oxidation reactions occurring within the cell release fluoride anions from the polymer membrane. And the fluoride anions promote corrosion of metal conductor plates and catalyst particles. Such degradation interferes with the function of the membrane and shortens the working life of the fuel cell.